Here's a look at the transactions this week that had the most important fantasy impact.
Kelly Johnson, 2B - acquired from Arizona for 2B Aaron Hill and IF John McDonald
Impact: The Blue Jays and Diamondbacks swapped struggling second basemen in the hopes that a trade might ignite their offense. Both Johnson and Hill have had good seasons in the past, but have been unable to get it going this season. Johnson hit just .209 in 114 games with Arizona this year, although he did hit 18 home runs. Hill's average was not much better, as he hit just .225 in 104 games with Toronto this year, with only six long balls. The trade isn't likely to affect either player's fantasy value much, unless a change of scenery lights a fire under one or both of them. McDonald is a defensive specialist who isn't likely to do anything with the bat while serving in a backup role.
Travis Hafner, DH - placed on the 15-day DL (foot)
Josh Judy, RHP - recalled from Triple-A Columbus
Impact: From 2004 to 2007, Hafner was a serious fantasy asset, as he averaged 32 home runs and 109 RBI a season over those four years. Unfortunately, injuries took their toll on the 34-year old DH, as he was limited to just 269 games from 2008 to 2010, during which he hit just 34 home runs. His average has remained solid, but he's clearly not the same player he once was. Hafner has landed on the DL for the second time this season, this time due to a strained right foot. He also missed about a month earlier this year with a strained oblique. Cleveland will likely use a variety of players in the DH spot while Hafner recovers. Judy gave the Indians' bullpen an extra arm before he was sent back down the next day.
Alex Rodriguez, 3B - activated from the 15-day DL
Aaron Laffey, LHP - optioned to Triple-A Scranton/Wilkes-Barre (and then designated for assignment)
Impact: Barring a miraculous final month and a half of the 2011 season, A-Rod's streak of 13 consecutive 100 RBI seasons will be snapped this year. He had been out since early July, when he injured his right knee and had to undergo surgery. He returns to a .295 average, 13 home runs, 53 runs scored and 52 RBI through 80 games. Eduardo Nunez filled in at the hot corner during Rodriguez's stint on the DL after filling in at short during Derek Jeter's DL stint. He has hit for a decent average while providing fantasy teams with some stolen bases, but will return to a backup role. Laffey made just one relief appearance for the Yankees after being acquired from the Mariners.
Jordan Schafer, CF - activated from the 15-day DL
Jordan Lyles, RHP - optioned to Triple-A Oklahoma City
Impact: Schafer finally made his Astros debut on Monday night after he was acquired from the Braves on July 31. He spent almost a month on the DL due to a chipped bone in his left middle finger that he suffered shortly before the trade. Schafer stole 15 bases and scored 32 runs in 52 games for Atlanta this season, but his other numbers have been no help to fantasy teams. He possesses very little power and has yet to prove that he can hit for average at the major league level. Lyles started 15 games for Houston this year, going 2-7 with an ERA of 5.02. He will be replaced in the rotation by J.A. Happ, who is expected to be recalled to start on Friday. He has been equally ineffective, going 4-14 with a 6.26 ERA in 22 starts for the Astros.
Brian Wilson, RHP - placed on the 15-day DL (elbow)
Steve Edlefsen, RHP - recalled from Triple-A Fresno
Impact: Wilson has become known as much for his giant beard as he has for his pitching, but there's no denying the fact that he's one of baseball's top closers. He saved a combined 127 games from 2008 to 2010, and was on pace this year to top the 40 mark for the third time in four years before he landed on the DL with elbow inflammation. The move was made retroactive to August 16, so he could be back as soon as next week. The Giants claimed Padres' closer Heath Bell off of waivers, but it's uncertain whether or not the two teams will be able to work out a deal. If not, Jeremy Affeldt and Ramon Ramirez appear to be the most likely candidates for save opportunities in San Francisco. Edlefsen gives the Giants' bullpen an extra arm, which they will likely use in a middle relief or mopup role.
Jonathon Niese - placed on the 15-day DL (ribs)
Mike Nickeas, C - called up from Triple-A Buffalo
Impact: The 24-year-old Niese is hopeful that he'll return this season as he attempts to recover from a strained right intercostal muscle. He originally suffered the injury during an at-bat in San Diego last week, and then aggravated it during his start against Philadelphia on Tuesday. He's 11-11 on the season, with a 4.40 ERA and 138 strikeouts in 157.1 innings. Miguel Batista, Chris Schwinden and Pat Misch have been mentioned as the most likely candidates to replace him in the rotation. All three are currently pitching for Triple-A Buffalo, and none should be considered a reliable fantasy asset. Nickeas will serve as the team's third catcher behind Josh Thole and Ronny Paulino.
Jimmy Rollins, SS - placed on the 15-day DL (groin)
Placido Polanco, 3B - activated from the 15-day DL
Impact: Rollins has rewarded his fantasy owners with plenty of runs and stolen bases this season, while improving his batting average by 25 points over last year. After an injury-plagued 2010, Rollins had remained healthy this season, playing in 121 of the Phillies' first 125 games. A groin strain will now sideline him for at least a couple of weeks, but Rollins is optimistic that he'll be back in action sometime in September. Wilson Valdez and Michael Martinez were covering third base while Placido Polanco was out, but will now shift over to short to cover for Rollins. Polanco will be playing through a sports hernia, and manager Charlie Manuel has said that his condition will be monitored closely. What that means is that Polanco will likely receive the occasional day off between now and the end of the season.
Cole Hamels, LHP - placed on the 15-day DL (shoulder)
Pete Orr, IF - recalled from Triple-A Lehigh Valley
Impact: As expected, Hamels has put together some impressive numbers this season, although he's pitched even better than most people could have expected. In 25 starts, the 27-year-old lefty has posted a 13-7 record to go along with an impressive ERA of 2.62 and a sparkling WHIP of just 0.99. His strikeout rate is down a bit from last season, but a rate of 8.11K/9 is still useful in pretty much any fantasy league. Inflammation in his left shoulder has cost him a couple of weeks, but with his DL assignment being made retroactive to August 13, he'll likely be back in action to take the hill against Cincinnati on Monday. Orr has done very little at the plate in 30 games with Philadelphia this season.
Kevin Correia, RHP - placed on the 15-day DL (oblique)
Chris Leroux, RHP - activated from the 15-day DL
Impact: Correia started off strong this year, earning himself a spot on the All-Star team, but has gotten progressively worse over the course of the season. In July and August, he went 2-5 while giving up 37 earned runs in 47 innings, for a 7.09 ERA. He has performed well on the road this year (10-3, 2.64 ERA), but has been absolutely terrible at home (2-8, 7.71). He becomes the latest in a long list of players who have landed on the DL this season due to a strained oblique. Ross Ohlendorf has since been activated from the DL to fill his spot in the rotation. Ohlendorf hadn't pitched since early April, when he suffered from a strained right shoulder. He, like Correia, is a middle-of-the-road starter who isn't likely to help a fantasy team with his mediocre ratios. Leroux returns to the bullpen after missing almost a month with a calf injury.